JP3365798B2 - Reflective objective - Google Patents
Reflective objectiveInfo
- Publication number
- JP3365798B2 JP3365798B2 JP29855292A JP29855292A JP3365798B2 JP 3365798 B2 JP3365798 B2 JP 3365798B2 JP 29855292 A JP29855292 A JP 29855292A JP 29855292 A JP29855292 A JP 29855292A JP 3365798 B2 JP3365798 B2 JP 3365798B2
- Authority
- JP
- Japan
- Prior art keywords
- mirror
- reflecting
- reflecting mirror
- objective
- distribution
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
Description
【０００１】[0001]
【産業上の利用分野】本発明は、顕微鏡等に用いられる
反射対物鏡に関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reflecting objective mirror used in microscopes and the like.
【０００２】[0002]
【従来の技術】従来、本発明の反射対物鏡と似たものに
は、一般の反射対物鏡や特公昭６３−２９７２３号等の
ものがある。2. Description of the Related Art Conventionally, there are general reflection objective mirrors and Japanese Patent Publication No. 63-29723 which are similar to the reflection objective mirror of the present invention.
【０００３】[0003]
【発明が解決しようとする課題】上記一般の反射対物鏡
（シュワルツシルド型）においては、その構成上、入射
光束の中心部の隠蔽が避けられず、輪帯開口となるた
め、解像力は上がるが、コントラストが落ち、像の見え
としてはあまり良くない。これは、ＭＴＦ（Ｍｏｄｕｒ
ａｔｉｏｎ Ｔｒａｎｓｆｅｒ Ｆｕｎｃｔｉｏｎ）カ
ーブに段差が付くことからも分る。特公昭６３−２９７
２３号のものでは、反射鏡の中心近傍を隠蔽することに
よって意図的に輪帯開口にし、低周波数のＭＴＦを犠牲
にして、高解像力を実現している。一方、一般にアポデ
ィゼーションと呼ばれる瞳変調（瞳の周辺部程その強度
が落ちる。）を施せば、解像力は少し落ちるが、コント
ラストが改善されることは周知であり、そのような特性
を持ったフィルタを反射対物鏡に組み合わせて、隠蔽に
よる影響を相殺させることも周知である。In the general reflective objective mirror (Schwarzschild type) described above, due to its configuration, concealment of the central portion of the incident light beam is unavoidable and a ring-shaped aperture is formed, so that the resolution is increased. , The contrast is reduced, and the appearance of the image is not very good. This is MTF (Modur
It is also known from the fact that there is a step on the ation transfer function curve. Japanese Examined Japanese Patent Publication No. 63-297
In No. 23, by concealing the vicinity of the center of the reflecting mirror, a ring-shaped aperture is intentionally formed, and high resolution is realized at the expense of low-frequency MTF. On the other hand, it is well known that if a pupil modulation generally called apodization (its intensity is reduced toward the periphery of the pupil), the resolution is slightly reduced, but the contrast is improved, and it has such characteristics. It is also known to combine filters with reflective objectives to offset the effects of concealment.
【０００４】これらの従来例は全て、強度・位相変調フ
ィルタを用いているが、反射光学系の中に屈折部材を挿
入することは、使用波長が限定されること等により望ま
しくない。Although all of these conventional examples use an intensity / phase modulation filter, it is not desirable to insert a refraction member in the reflection optical system because the wavelength used is limited.
【０００５】本発明はこのような問題点に鑑みてなされ
たものであり、その目的は、反射光学系中に屈折部材を
用いることなく、構造に基づく一部光束の隠蔽によるコ
ントラスト低下等を相殺し得る瞳変調を施した反射対物
鏡を提供することである。The present invention has been made in view of the above problems, and an object thereof is to cancel the reduction in contrast due to the concealment of a partial light beam due to the structure without using a refraction member in the reflection optical system. To provide a reflective objective with a possible pupil modulation.
【０００６】[0006]
【課題を解決するための手段】上記目的を達成する本発
明の反射対物鏡は、第１の反射鏡と、該第１の反射鏡よ
りも小さい外径を有する第２の反射鏡を少なくとも備
え、光束の中心部が前記第２の反射鏡により遮蔽されて
前記第１の反射鏡に入射するように光束中に配置される
反射対物鏡であって、前記第１の反射鏡と前記第２の反
射鏡が所定の間隔で配置されると共に、前記第２の反射
鏡が前記第１の反射鏡の中心に位置し、前記第２の反射
鏡の反射面の反射率が中心に比べて周辺程低下するよう
に構成して瞳変調を行うことを特徴とするものである。A reflecting objective mirror of the present invention which achieves the above object comprises at least a first reflecting mirror and a second reflecting mirror having an outer diameter smaller than that of the first reflecting mirror. A reflecting objective mirror arranged in the light flux so that a central portion of the light flux is shielded by the second reflecting mirror and incident on the first reflecting mirror, wherein the first reflecting mirror and the second reflecting mirror Second reflecting mirrors are arranged at a predetermined interval, the second reflecting mirror is located at the center of the first reflecting mirror, and the reflectance of the reflecting surface of the second reflecting mirror is higher than the center. It is characterized in that it is configured so as to decrease as much as possible to perform pupil modulation.
【０００７】[0007]
【作用】一般に、シュワルツシルド型の反射対物鏡を設
計すると、小鏡がほぼ瞳位置にくる。そこで、この反射
面の反射率分布を制御して、反射強度によりアポディゼ
ーションを行えば、シュワルツシルド型の反射対物鏡に
不可避の欠点である、中心光束隠蔽によるコントラスト
低下を相殺することができる。また、他のタイプの反射
対物鏡でも、何れかの反射面が瞳位置近くにくるため、
その反射面で上記のアポディゼーションを行えばよい。In general, when a Schwarzschild type reflecting objective is designed, the small mirror comes close to the pupil position. Therefore, by controlling the reflectance distribution of this reflecting surface and performing apodization by the reflection intensity, it is possible to offset the contrast reduction due to the concealment of the central light beam, which is an unavoidable defect of the Schwarzschild type reflecting objective mirror. . Also, in other types of reflective objectives, either reflecting surface comes close to the pupil position,
The apodization described above may be performed on the reflecting surface.
【０００８】また、ステージスキャン方式のレーザ走査
顕微鏡のように、軸上しか使用しない装置の反射光学系
の場合は、瞳位置にこだわることなく、光学系の任意の
反射面で上記のアポディゼーションを行えばよく、さら
に、製作の容易さから、２面以上の反射面で反射率分布
制御を行ってもよいが、その効果は等価な１面での反射
率分布制御と同じであることは言うまでもない。Further, in the case of a reflection optical system of a device which is used only on the axis, such as a stage scanning type laser scanning microscope, the apodization described above is performed on an arbitrary reflection surface of the optical system without focusing on the pupil position. In addition, the reflectance distribution control may be performed with two or more reflecting surfaces for ease of manufacturing, but the effect is the same as the equivalent reflectance distribution control with one surface. Needless to say.
【０００９】[0009]
【実施例】以下に、図面を参照にして本発明の反射対物
鏡の実施例について説明する。図１に一般的なシュワル
ツシルド型の反射対物鏡の断面図を示す。この光学系
は、中心に孔を有する大鏡１と小鏡２からなり、物点Ｏ
から出た光束の中心部は、小鏡２により隠蔽されて大鏡
１に入射する。このような反射対物鏡の１例のレンズデ
ータを以下に示す。ここで、記号は、Ｍは倍率、ＮＡは
開口数、ｒ1 、ｒ2 …は各面の曲率半径、ｄ1 、ｄ2 …
は各面間の間隔であり、また、非球面形状は、光軸方向
をｘ、光軸に直交する方向をｙとした時、次の式で表さ
れる。
ｘ=(ｙ2/ｒ）／［１＋｛１−（１＋Ｋ）ｙ2/ｒ2 ｝1/2 ］
＋A4ｙ4 ＋A6ｙ6 ＋A8ｙ8 ＋ A10ｙ10
ただし、ｒは近軸曲率半径、Ｋは円錐係数、A4、A6、
A8、A10 は非球面係数である。DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the reflective objective mirror of the present invention will be described below with reference to the drawings. FIG. 1 shows a cross-sectional view of a general Schwarzschild type reflection objective mirror. This optical system comprises a large mirror 1 and a small mirror 2 each having a hole at the center, and an object point O
The central portion of the light flux emitted from the light source is hidden by the small mirror 2 and enters the large mirror 1. The lens data of an example of such a reflective objective is shown below. Here, symbols are M for magnification, NA for numerical aperture, r 1 , r 2 ... Radius of curvature of each surface, d 1 , d 2 ...
Is the distance between the surfaces, and the aspherical shape is expressed by the following equation, where x is the optical axis direction and y is the direction orthogonal to the optical axis. x = (y 2 / r) / [1+ {1- (1 + K) y 2 / r 2} 1/2] + A 4 y 4 + A 6 y 6 + A 8 y 8 + A 10 y 10 where, r is the paraxial Radius of curvature, K is conic coefficient, A 4 , A 6 ,
A 8 and A 10 are aspherical coefficients.
【００１０】反射対物鏡の１例
Ｍ＝80× ，ＮＡ＝0.7500
ｒ1 （物点Ｏ） = ∞ ｄ1 = 36.5
726
ｒ2 （大鏡１） = -31.7707 ｄ2 =-26.1
738
ｒ3 （小鏡２） = -3.8562（非球面） ｄ3 = 49.6
012
ｒ4 （仮想面３）= ∞ ｄ4 =150.0
000
ｒ5 （像面） = ∞
非球面係数
第３面
Ｋ =1.2148
A4 = 0.1755 ×10-2
A6 = 0.2302 ×10-3
A8 = 0.8503 ×10-5
A10= 0.8105 ×10-5
この反射対物鏡の隠蔽率（ｍｉｎＮＡ／ｍａｘＮＡ）は
２０％であり、このままでは図２、図５に曲線Ａで示す
ようなＭＴＦとなり、コントラストが落ちてしまう。One example of a reflecting objective mirror M = 80 ×, NA = 0.7500 r 1 (object point O) = ∞ d 1 = 36.5
726 r 2 (large mirror 1) = -31.7707 d 2 = -26.1
738 r 3 (small mirror 2) = -3.8562 (aspherical surface) d 3 = 49.6
012 r 4 (virtual surface 3) = ∞ d 4 = 150.0
000 r 5 (image surface) = ∞ Aspherical coefficient 3rd surface K = 1.2148 A 4 = 0.1755 × 10 -2 A 6 = 0.2302 × 10 -3 A 8 = 0.8503 × 10 -5 A 10 = 0.8105 × 10 -5 The concealment ratio (minNA / maxNA) of this reflective objective lens is 20%, and if it is left as it is, the MTF as shown by the curve A in FIGS.
【００１１】図３は、本発明の第１実施例のアポディゼ
ーション反射面の反射率分布を示している。このような
反射率分布を図１の小鏡２に持たせる。この反射率分布
は、反射面の中心を軸としたガウス分布である。これに
よるＭＴＦは、図２の曲線Ｂのようになり、中心光束隠
蔽によるコントラストの低下が相殺され、かつ、ＭＴＦ
カーブも素直になっていることから、像が改善されてい
ることが分る。FIG. 3 shows the reflectance distribution of the apodization reflecting surface of the first embodiment of the present invention. The small mirror 2 shown in FIG. 1 has such a reflectance distribution. This reflectance distribution is a Gaussian distribution with the center of the reflecting surface as the axis. The MTF resulting from this is as shown by the curve B in FIG. 2, and the decrease in contrast due to the concealment of the central luminous flux is offset, and the MTF is
Since the curve is also straightforward, it can be seen that the image has been improved.
【００１２】図４は、第２実施例のアポディゼーション
反射面の反射率分布を示している。同様に図１の小鏡２
に反射率分布を持たせている。この反射率分布は、反射
面の中心を軸としたステップ分布である。これによるＭ
ＴＦは、図５の曲線Ｂのようになり、中心光束隠蔽によ
るコントラストの低下が多少相殺され、かつ、ＭＴＦカ
ーブが素直になっていることから、やはり像が改善され
ていることが分る。FIG. 4 shows the reflectance distribution of the apodization reflecting surface of the second embodiment. Similarly, the small mirror 2 of FIG.
Has a reflectance distribution. This reflectance distribution is a step distribution with the center of the reflecting surface as the axis. M by this
The TF is as shown by the curve B in FIG. 5, and the deterioration of the contrast due to the concealment of the central luminous flux is offset to some extent, and the MTF curve is straightforward, which indicates that the image is also improved.
【００１３】以上、本発明の反射対物鏡を実施例に基づ
いて説明してきたが、本発明はこれら実施例に限定され
ず種々の変形が可能である。また、本発明の考え方を適
用する反射光学系も、図１のようなシュワルツシルド型
の反射対物鏡に限定されず、単数又は複数の反射面から
なる他の形式のものであってもよい。The reflective objective mirror of the present invention has been described above based on the embodiments, but the present invention is not limited to these embodiments and various modifications can be made. Further, the reflective optical system to which the concept of the present invention is applied is not limited to the Schwarzschild type reflective objective mirror as shown in FIG. 1 and may be another type having a single or a plurality of reflecting surfaces.
【００１４】[0014]
【発明の効果】以上の説明から明らかなように、本発明
の反射対物鏡によると、屈折部材を用いることなく、一
部光学素子による光束隠蔽による像の劣化等を相殺し得
る瞳変調を施した反射対物鏡を得ることができる。As is apparent from the above description, according to the reflective objective lens of the present invention, the pupil modulation that cancels the image deterioration due to the light beam concealment by the partial optical element can be performed without using the refraction member. It is possible to obtain a reflective objective mirror.
【図１】本発明を適用する一般的なシュワルツシルド型
の反射対物鏡の断面図である。FIG. 1 is a cross-sectional view of a general Schwarzschild type reflecting objective to which the present invention is applied.
【図２】本発明の第１実施例適用前後のＭＴＦを示す図
である。FIG. 2 is a diagram showing MTFs before and after applying the first embodiment of the present invention.
【図３】本発明の第１実施例のアポディゼーション反射
面の反射率分布を示す図である。FIG. 3 is a diagram showing a reflectance distribution of an apodization reflecting surface according to the first embodiment of the present invention.
【図４】第２実施例のアポディゼーション反射面の反射
率分布を示す図である。FIG. 4 is a diagram showing a reflectance distribution of an apodization reflecting surface of a second example.
【図５】第２実施例適用前後のＭＴＦを示す図である。FIG. 5 is a diagram showing MTF before and after application of the second embodiment.
１…大鏡 ２…小鏡 ３…仮想面 1 ... Large mirror 2 ... small mirror 3 ... Virtual plane
───────────────────────────────────────────────────── フロントページの続き (58)調査した分野(Int.Cl.7，ＤＢ名) G02B 27/58 G02B 17/00 ─────────────────────────────────────────────────── ─── Continuation of the front page (58) Fields surveyed (Int.Cl. 7 , DB name) G02B 27/58 G02B 17/00
Claims (3)
小さい外径を有する第２の反射鏡を少なくとも備え、光
束の中心部が前記第２の反射鏡により遮蔽されて前記第
１の反射鏡に入射するように光束中に配置される反射対
物鏡であって、 前記第１の反射鏡と前記第２の反射鏡が所定の間隔で配
置されると共に、前記第２の反射鏡が前記第１の反射鏡
の中心に位置し、前記第２の反射鏡の反射面の反射率が
中心に比べて周辺程低下するように構成して瞳変調を行
うことを特徴とする反射対物鏡。1. A first reflector and more than the first reflector
Comprising at least a second reflecting mirror having a small outer diameter, light
The central portion of the bundle is shielded by the second reflecting mirror and
Reflection pair arranged in the light beam so as to be incident on the reflecting mirror of No. 1
An object mirror, wherein the first reflecting mirror and the second reflecting mirror are arranged at a predetermined interval, and the second reflecting mirror is located at the center of the first reflecting mirror; The reflecting objective mirror is characterized in that the reflectance of the reflecting surface of the reflecting mirror is lower in the peripheral portion than in the central portion to perform pupil modulation.
軸としてガウス分布であることを特徴とする請求項１記
載の反射対物鏡。2. The reflective objective mirror according to claim 1, wherein the reflectance distribution is a Gaussian distribution with the center of the reflecting surface as an axis.
軸としたステップ分布であることを特徴とする請求項１
記載の反射対物鏡。3. The distribution of the reflectance is a step distribution with the center of the reflecting surface as an axis.
The reflective objective described.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP29855292A JP3365798B2 (en) | 1992-11-09 | 1992-11-09 | Reflective objective |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP29855292A JP3365798B2 (en) | 1992-11-09 | 1992-11-09 | Reflective objective |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH06148574A JPH06148574A (en) | 1994-05-27 |
| JP3365798B2 true JP3365798B2 (en) | 2003-01-14 |
Family
ID=17861216
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP29855292A Expired - Fee Related JP3365798B2 (en) | 1992-11-09 | 1992-11-09 | Reflective objective |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3365798B2 (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US9341831B2 (en) | 2011-06-10 | 2016-05-17 | Canon Kabushiki Kaisha | Optical system with catadioptric optical subsystem |
| EP3730988A4 (en) | 2017-12-18 | 2021-09-08 | Yokogawa Electric Corporation | Objective optical system and microscope system |
-
1992
- 1992-11-09 JP JP29855292A patent/JP3365798B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPH06148574A (en) | 1994-05-27 |
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